Background: Hemoglobin A1c levels and blood sugar is a diagnostic tests used for diabetes and to determine the developing of diabetic complications. The level of HbA1c is affected by factors such as the Haemoglobin, the age of RBCs in the blood circulation and the Hb glycation rate. The aim of this retrospective study is to assess the relationship of HbA1c levels and blood sugar with haemoglobin concentration, and RBC parameter during female clinic follow-up. Material and Method: The HbA1c levels of 202 patients was measured by NycoCard reader II analyzer and RBC, Haemoglobin concentration (Hb), hematocrit (Hct), Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC) was measured by mindray BC-3000 Plus auto haematology analyzer, the statistical analyses were performed with SPSS software version 16.0. The Spearman correlation coefficient was used for the relationship of HbA1c, blood sugar with RBC parameters and Kruskal Wallis test for the comparison of HbA1c and RBC parameters between the Diabetics, pre-diabetic and non-diabetic patients. Results: The correlation of HbA1c and blood sugar levels with RBC parameter indicates positive correlation with RBC count and negative correlation with MCV and MCH, and the comparison among diabetic, pre-diabetic and non-diabetic patients, the results showed significantly higher mean of RBC count, Hb concentration and Hct in diabetic patients, and the mean MCV and MCH were significantly higher in non-diabetic compared with pre-diabetic and diabetic. Conclusion: The low level of HbA1c has been found in shorten RBCs lifespan, which is affected by RBC parameters and decrease of RBC lifespan in hyperglycaemia patients. Therefore, this study concludes that the RBC parameters are an excellent tool parallel with HbA1c and blood sugar for the assessment of diabetes patients.